Synthesis of nanocomposites thin films by coupling a nanoparticle jet and PVD

International audienceWe present here an original safe-by-design method for the elaboration of nanostructuredfilms composed of nanoparticles embedded in a matrix. This versatile single step processoperates under vacuum by combining the jet of nanoparticles technology with classicalmagnetron sputtering. The general scheme of the process is presented in Fig. 1. Versatilitymajor advantage of the technique comes from the possibility to choose independently thechemical nature of nanoparticles and matrix [1,2]. Moreover, it is possible to use any source ofnanoparticles in gas phase. For example, nanoparticles can be synthesized in-situ by laser drivenpyrolysis or it is possible to use an atomizer producing an aerosol from colloidal suspension ofpreviously synthesized nanoparticles. Laser pyrolysis is an efficient method to synthesizevarious high purity nanopowders, oxides and non-oxides, in a gas phase bottom-up approach[3].The possibility to achieve nanocomposites syntheses without limitation in chemicalcomposition of the nanoparticles and the matrix is made possible by using an aerodynamic lensimplemented on the experimental set up between the source of nanoparticles and the depositionchamber (Figure 1a). The lens is composed of successive chambers separated by diaphragmsand when nanoparticles in aerosol go through the lens thanks to a differential pumping, theyare progressively concentrated in a focused beam [4]. This beam can be used for gas phasecharacterization of freestanding nanoparticles [5] or due to a high deposition speed for 3D NANO 2016, Québec, Canadaprinting. Moreover, numerical and experimental studies show that is possible to obtain adivergent and homogenous jet of nanoparticles by adapting the geometry of the lens (Fig.2). Asthe speed acquired by the nanoparticles is high [6], their kinetic energy is sufficient to passthrough the relatively high pressure (around 5.10-3 mbar) deposition chamber and get depositedon a substrate at a distance of 20 cm. The pressure in this chamber is adequate for running aclassical magnetron sputtering device used to deposit, on the same substrate and at the sametime, the material constituting the matrix of the composite film.We explored this possibility to make large and homogenous films of nanoparticles andfirst samples are composed of gold and silicon nanoparticles. Many applications are alreadyconsidered for this type of coating: photovoltaic, aesthetic coating for luxury industry, hardcovering for tools or self-healing films